Alice Fisher, Sister Jacobine, is an agent of the Pope.
By that I mean that she is the assassin for the Pontiff; the tool to used when nothing else will work and the problem to be solved must be done with the most final of options. Keeping this particular option secret is understandably quite important and it has been so for the several hundred years that Sister Jacobine has been working at the job.
In most instances when speaking of a person having been doing a task for 'hundreds of years' it would be taken that different people have been filling the role over those many decades but not in this case. Here, Sister Jacobine who is using the covername of Alice Fisher, is the same person throughout.
"My name isn't Alice Fisher. I have no idea what my birth name is. Was. Since my fifteenth year, I have been Sister Jacobine of the Order of Fontevraud, Amesbury Priory, Wiltshire. I currently reside in the Apostolic Palace in Vatican City. I am here at the behest of his holiness, Pope Benedict the Seventeenth."
That is the first glimpse of the truth behind her. We learn soon thereafter that she was born on Christmas Day in the year 1491. Her parents, being very poor and unable to provide for another girl child, left her with the nuns at the Priory, a not unusual event in those days. And for the next couple of years there seemed nothing unusual about the child; she was a normal baby and then little girl. That normalcy changed drastically when she was around 3 and an accident happened in the play yard and she was accidentally hurt in the face very badly with much blood and what would likely have been permanent facial damage. But as the attending nuns were cleaning her up, they literally watched her body heal itself. Within minutes, there was no sign of any trauma except the drying blood.
The times being what they were, it would not have been surprising to have the little girl declared a witch and something horrible done (or tried to be done) to her. Luckily for her the Mother Superior took the opposite view and decided her gift was one from God. For the next dozen years she remained with the Order and took the vows herself. We are not told (as of this writing) how she went from being a nun in a convent to being the enforcement arm for every Pope since that time but it has to be a fascinating story itself.
The Sister is by no means invulnerable. In the course of the short adventures we have so far of her, she is shot a couple of times but her miraculous healing begins immediately from the inside out, pushing the foreign bullet out of her as it happens. She has also over the years learned that her blood carries that healing power with it and can be used to help others if applied in time.
Sister Jacobine appears to be around 25 years of age, the point where her aging finally stopped. She is described as being very beautiful albeit quite short with the top of her head often not coming to the shoulders of the men she has to confront. Her body has been maintained in splendid fighting condition and over the years she has learned a wide assortment of fighting styles as well as being constantly up-to-date with any weaponry from swords to muskets to pistols.
"She was glad the requirement of wearing a habit had been done away with years ago. Although she did prefer to wear the traditional black veil with white banding, the long and flowing robes always snagged on the barrel of the gun and the blood stained them. Knives and short broadswords had also been a problem. The habit had often ended up torn, in addition to bloody."
Though she is now over five hundred years old, Sister Jacobine has maintained many of her ingrained attitudes. She does not like swearing. She prefers to use older terms for things, such as calling any policeman 'constable'. She is also quite human, though, and sparingly enjoys the pleasure of the opposite sex (she strives to not get closely attached to anyone since she hates seeing them age and die). She is definitely not adverse to Bushmills, taking it usually neat.